Personally it would be claymore, often hailed as a female centric berserk.
A story about the lowest class of a generation of engineered superhuman woman fighting monsters to save humanity.
The art gets better and better as it goes on, with stunning panels everywhere(example below).
The intrigue struggle and strive the characters go through is a stellar example of simple yet effective storytelling.
Alternate recommendation that won't sacrifice your emotional well-being for the sake of good storytelling:
One Punch Man is a shockingly good read. It's not exactly an earth shattering narrative like Goodnight Punpun, but it is equally a one-of-a-kind manga/anime.
You wouldn't think a story where the protagonist is effectively invincible and seemingly infinitely powerful would be interesting, but they do A LOT with the premise. The action is great, but the side-characters really form the meat of the story, and there's a lot of genuinely wholesome, funny, and sometimes sad moments.
The anime is very faithful to the manga, so I recommend them both. However the anime is very far behind in the story, so you'll inevitably end up reading the manga if you enjoy the story.